WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/mm/as.c


/*
 * Copyright (C) 2001-2006 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
/*
 * This file contains address space manipulation functions.
 * Roughly speaking, this is a higher-level client of
 * Virtual Address Translation (VAT) subsystem.
 */
 
#include <mm/as.h>
#include <arch/mm/as.h>
#include <mm/page.h>
#include <mm/frame.h>
#include <mm/slab.h>
#include <mm/tlb.h>
#include <arch/mm/page.h>
#include <genarch/mm/page_pt.h>
#include <mm/asid.h>
#include <arch/mm/asid.h>
#include <arch/types.h>
#include <typedefs.h>
#include <synch/spinlock.h>
#include <config.h>
#include <adt/list.h>
#include <panic.h>
#include <arch/asm.h>
#include <debug.h>
#include <memstr.h>
#include <arch.h>
#include <print.h>
 
as_operations_t *as_operations = NULL;
 
/** Address space lock. It protects inactive_as_with_asid_head. */
SPINLOCK_INITIALIZE(as_lock);
 
/**
 * This list contains address spaces that are not active on any
 * processor and that have valid ASID.
 */
LIST_INITIALIZE(inactive_as_with_asid_head);
 
/** Kernel address space. */
as_t *AS_KERNEL = NULL;
 
static int get_area_flags(as_area_t *a);
 
/** Initialize address space subsystem. */
void as_init(void)
{
    as_arch_init();
    AS_KERNEL = as_create(FLAG_AS_KERNEL);
        if (!AS_KERNEL)
                panic("can't create kernel address space\n");
}
 
/** Create address space.
 *
 * @param flags Flags that influence way in wich the address space is created.
 */
as_t *as_create(int flags)
{
    as_t *as;
 
    as = (as_t *) malloc(sizeof(as_t), 0);
    link_initialize(&as->inactive_as_with_asid_link);
    spinlock_initialize(&as->lock, "as_lock");
    list_initialize(&as->as_area_head);
   
    if (flags & FLAG_AS_KERNEL)
        as->asid = ASID_KERNEL;
    else
        as->asid = ASID_INVALID;
   
    as->refcount = 0;
    as->page_table = page_table_create(flags);
 
    return as;
}
 
/** Create address space area of common attributes.
 *
 * The created address space area is added to the target address space.
 *
 * @param as Target address space.
 * @param type Type of area.
 * @param size Size of area in multiples of PAGE_SIZE.
 * @param base Base address of area.
 *
 * @return Address space area on success or NULL on failure.
 */
as_area_t *as_area_create(as_t *as, as_area_type_t type, size_t size, __address base)
{
    ipl_t ipl;
    as_area_t *a;
   
    if (base % PAGE_SIZE)
        panic("addr not aligned to a page boundary");
   
    ipl = interrupts_disable();
    spinlock_lock(&as->lock);
   
    /*
     * TODO: test as_area which is to be created doesn't overlap with an existing one.
     */
   
    a = (as_area_t *) malloc(sizeof(as_area_t), 0);
 
    spinlock_initialize(&a->lock, "as_area_lock");
   
    link_initialize(&a->link);         
    a->type = type;
    a->size = size;
    a->base = base;
   
    list_append(&a->link, &as->as_area_head);
 
    spinlock_unlock(&as->lock);
    interrupts_restore(ipl);
 
    return a;
}
 
/** Initialize mapping for one page of address space.
 *
 * This functions maps 'page' to 'frame' according
 * to attributes of the address space area to
 * wich 'page' belongs.
 *
 * @param as Target address space.
 * @param page Virtual page within the area.
 * @param frame Physical frame to which page will be mapped.
 */
void as_set_mapping(as_t *as, __address page, __address frame)
{
    as_area_t *a, *area = NULL;
    link_t *cur;
    ipl_t ipl;
   
    ipl = interrupts_disable();
    spinlock_lock(&as->lock);
   
    /*
     * First, try locate an area.
     */
    for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
        a = list_get_instance(cur, as_area_t, link);
        spinlock_lock(&a->lock);
 
        if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
            area = a;
            break;
        }
       
        spinlock_unlock(&a->lock);
    }
   
    if (!area) {
        panic("page not part of any as_area\n");
    }
 
    /*
     * Note: area->lock is held.
     */
   
    page_mapping_insert(as, page, frame, get_area_flags(area));
   
    spinlock_unlock(&area->lock);
    spinlock_unlock(&as->lock);
    interrupts_restore(ipl);
}
 
/** Handle page fault within the current address space.
 *
 * This is the high-level page fault handler.
 * Interrupts are assumed disabled.
 *
 * @param page Faulting page.
 *
 * @return 0 on page fault, 1 on success.
 */
int as_page_fault(__address page)
{
    link_t *cur;
    as_area_t *a, *area = NULL;
    __address frame;
   
    ASSERT(AS);
    spinlock_lock(&AS->lock);
   
    /*
     * Search this areas of this address space for presence of 'page'.
     */
    for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {
        a = list_get_instance(cur, as_area_t, link);
        spinlock_lock(&a->lock);
 
        if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
 
            /*
             * We found the area containing 'page'.
             * TODO: access checking
             */
            area = a;
            break;
        }
       
        spinlock_unlock(&a->lock);
    }
   
    if (!area) {
        /*
         * No area contained mapping for 'page'.
         * Signal page fault to low-level handler.
         */
        spinlock_unlock(&AS->lock);
        return 0;
    }
 
    /*
     * Note: area->lock is held.
     */
   
    /*
     * In general, there can be several reasons that
     * can have caused this fault.
     *
     * - non-existent mapping: the area is a scratch
     *   area (e.g. stack) and so far has not been
     *   allocated a frame for the faulting page
     *
     * - non-present mapping: another possibility,
     *   currently not implemented, would be frame
     *   reuse; when this becomes a possibility,
     *   do not forget to distinguish between
     *   the different causes
     */
    frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
    memsetb(PA2KA(frame), FRAME_SIZE, 0);
   
    /*
     * Map 'page' to 'frame'.
     * Note that TLB shootdown is not attempted as only new information is being
     * inserted into page tables.
     */
    page_mapping_insert(AS, page, frame, get_area_flags(area));
   
    spinlock_unlock(&area->lock);
    spinlock_unlock(&AS->lock);
 
    return 1;
}
 
/** Switch address spaces.
 *
 * @param old Old address space or NULL.
 * @param new New address space.
 */
void as_switch(as_t *old, as_t *new)
{
    ipl_t ipl;
    bool needs_asid = false;
   
    ipl = interrupts_disable();
    spinlock_lock(&as_lock);
 
    /*
     * First, take care of the old address space.
     */
    if (old) {
        spinlock_lock(&old->lock);
        ASSERT(old->refcount);
        if((--old->refcount == 0) && (old != AS_KERNEL)) {
            /*
             * The old address space is no longer active on
             * any processor. It can be appended to the
             * list of inactive address spaces with assigned
             * ASID.
             */
             ASSERT(old->asid != ASID_INVALID);
             list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
        }
        spinlock_unlock(&old->lock);
    }
 
    /*
     * Second, prepare the new address space.
     */
    spinlock_lock(&new->lock);
    if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
        if (new->asid != ASID_INVALID)
            list_remove(&new->inactive_as_with_asid_link);
        else
            needs_asid = true;  /* defer call to asid_get() until new->lock is released */
    }
    SET_PTL0_ADDRESS(new->page_table);
    spinlock_unlock(&new->lock);
 
    if (needs_asid) {
        /*
         * Allocation of new ASID was deferred
         * until now in order to avoid deadlock.
         */
        asid_t asid;
       
        asid = asid_get();
        spinlock_lock(&new->lock);
        new->asid = asid;
        spinlock_unlock(&new->lock);
    }
    spinlock_unlock(&as_lock);
    interrupts_restore(ipl);
   
    /*
     * Perform architecture-specific steps.
     * (e.g. write ASID to hardware register etc.)
     */
    as_install_arch(new);
   
    AS = new;
}
 
/** Compute flags for virtual address translation subsytem.
 *
 * The address space area must be locked.
 * Interrupts must be disabled.
 *
 * @param a Address space area.
 *
 * @return Flags to be used in page_mapping_insert().
 */
int get_area_flags(as_area_t *a)
{
    int flags;
 
    switch (a->type) {
        case AS_AREA_TEXT:
            flags = PAGE_EXEC | PAGE_READ | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
            break;
        case AS_AREA_DATA:
        case AS_AREA_STACK:
            flags = PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
            break;
        default:
            panic("unexpected as_area_type_t %d", a->type);
    }
   
    return flags;
}
 
/** Create page table.
 *
 * Depending on architecture, create either address space
 * private or global page table.
 *
 * @param flags Flags saying whether the page table is for kernel address space.
 *
 * @return First entry of the page table.
 */
pte_t *page_table_create(int flags)
{
        ASSERT(as_operations);
        ASSERT(as_operations->page_table_create);
 
        return as_operations->page_table_create(flags);
}
 

Rev 823	Rev 840
1	/*	1	/*
2	* Copyright (C) 2001-2006 Jakub Jermar	2	* Copyright (C) 2001-2006 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/*	29	/*
30	* This file contains address space manipulation functions.	30	* This file contains address space manipulation functions.
31	* Roughly speaking, this is a higher-level client of	31	* Roughly speaking, this is a higher-level client of
32	* Virtual Address Translation (VAT) subsystem.	32	* Virtual Address Translation (VAT) subsystem.
33	*/	33	*/
34		34
35	#include <mm/as.h>	35	#include <mm/as.h>
36	#include <arch/mm/as.h>	36	#include <arch/mm/as.h>
37	#include <mm/page.h>	37	#include <mm/page.h>
38	#include <mm/frame.h>	38	#include <mm/frame.h>
39	#include <mm/slab.h>	39	#include <mm/slab.h>
40	#include <mm/tlb.h>	40	#include <mm/tlb.h>
41	#include <arch/mm/page.h>	41	#include <arch/mm/page.h>
42	#include <genarch/mm/page_pt.h>	42	#include <genarch/mm/page_pt.h>
43	#include <mm/asid.h>	43	#include <mm/asid.h>
44	#include <arch/mm/asid.h>	44	#include <arch/mm/asid.h>
45	#include <arch/types.h>	45	#include <arch/types.h>
46	#include <typedefs.h>	46	#include <typedefs.h>
47	#include <synch/spinlock.h>	47	#include <synch/spinlock.h>
48	#include <config.h>	48	#include <config.h>
49	#include <adt/list.h>	49	#include <adt/list.h>
50	#include <panic.h>	50	#include <panic.h>
51	#include <arch/asm.h>	51	#include <arch/asm.h>
52	#include <debug.h>	52	#include <debug.h>
53	#include <memstr.h>	53	#include <memstr.h>
54	#include <arch.h>	54	#include <arch.h>
55	#include <print.h>	55	#include <print.h>
56		56
57	as_operations_t *as_operations = NULL;	57	as_operations_t *as_operations = NULL;
58		58
59	/** Address space lock. It protects inactive_as_with_asid_head. */	59	/** Address space lock. It protects inactive_as_with_asid_head. */
60	SPINLOCK_INITIALIZE(as_lock);	60	SPINLOCK_INITIALIZE(as_lock);
61		61
62	/**	62	/**
63	* This list contains address spaces that are not active on any	63	* This list contains address spaces that are not active on any
64	* processor and that have valid ASID.	64	* processor and that have valid ASID.
65	*/	65	*/
66	LIST_INITIALIZE(inactive_as_with_asid_head);	66	LIST_INITIALIZE(inactive_as_with_asid_head);
67		67
68	/** Kernel address space. */	68	/** Kernel address space. */
69	as_t *AS_KERNEL = NULL;	69	as_t *AS_KERNEL = NULL;
70		70
71	static int get_area_flags(as_area_t *a);	71	static int get_area_flags(as_area_t *a);
72		72
73	/** Initialize address space subsystem. */	73	/** Initialize address space subsystem. */
74	void as_init(void)	74	void as_init(void)
75	{	75	{
76	as_arch_init();	76	as_arch_init();
77	AS_KERNEL = as_create(FLAG_AS_KERNEL);	77	AS_KERNEL = as_create(FLAG_AS_KERNEL);
78	if (!AS_KERNEL)	78	if (!AS_KERNEL)
79	panic("can't create kernel address space\n");	79	panic("can't create kernel address space\n");
80	}	80	}
81		81
82	/** Create address space.	82	/** Create address space.
83	*	83	*
84	* @param flags Flags that influence way in wich the address space is created.	84	* @param flags Flags that influence way in wich the address space is created.
85	*/	85	*/
86	as_t *as_create(int flags)	86	as_t *as_create(int flags)
87	{	87	{
88	as_t *as;	88	as_t *as;
89		89
90	as = (as_t *) malloc(sizeof(as_t), 0);	90	as = (as_t *) malloc(sizeof(as_t), 0);
91	link_initialize(&as->inactive_as_with_asid_link);	91	link_initialize(&as->inactive_as_with_asid_link);
92	spinlock_initialize(&as->lock, "as_lock");	92	spinlock_initialize(&as->lock, "as_lock");
93	list_initialize(&as->as_area_head);	93	list_initialize(&as->as_area_head);
94		94
95	if (flags & FLAG_AS_KERNEL)	95	if (flags & FLAG_AS_KERNEL)
96	as->asid = ASID_KERNEL;	96	as->asid = ASID_KERNEL;
97	else	97	else
98	as->asid = ASID_INVALID;	98	as->asid = ASID_INVALID;
99		99
100	as->refcount = 0;	100	as->refcount = 0;
101	as->page_table = page_table_create(flags);	101	as->page_table = page_table_create(flags);
102		102
103	return as;	103	return as;
104	}	104	}
105		105
106	/** Create address space area of common attributes.	106	/** Create address space area of common attributes.
107	*	107	*
108	* The created address space area is added to the target address space.	108	* The created address space area is added to the target address space.
109	*	109	*
110	* @param as Target address space.	110	* @param as Target address space.
111	* @param type Type of area.	111	* @param type Type of area.
112	* @param size Size of area in multiples of PAGE_SIZE.	112	* @param size Size of area in multiples of PAGE_SIZE.
113	* @param base Base address of area.	113	* @param base Base address of area.
114	*	114	*
115	* @return Address space area on success or NULL on failure.	115	* @return Address space area on success or NULL on failure.
116	*/	116	*/
117	as_area_t as_area_create(as_t as, as_area_type_t type, size_t size, __address base)	117	as_area_t as_area_create(as_t as, as_area_type_t type, size_t size, __address base)
118	{	118	{
119	ipl_t ipl;	119	ipl_t ipl;
120	as_area_t *a;	120	as_area_t *a;
121		121
122	if (base % PAGE_SIZE)	122	if (base % PAGE_SIZE)
123	panic("addr not aligned to a page boundary");	123	panic("addr not aligned to a page boundary");
124		124
125	ipl = interrupts_disable();	125	ipl = interrupts_disable();
126	spinlock_lock(&as->lock);	126	spinlock_lock(&as->lock);
127		127
128	/*	128	/*
129	* TODO: test as_area which is to be created doesn't overlap with an existing one.	129	* TODO: test as_area which is to be created doesn't overlap with an existing one.
130	*/	130	*/
131		131
132	a = (as_area_t *) malloc(sizeof(as_area_t), 0);	132	a = (as_area_t *) malloc(sizeof(as_area_t), 0);
133		133
134	spinlock_initialize(&a->lock, "as_area_lock");	134	spinlock_initialize(&a->lock, "as_area_lock");
135		135
136	link_initialize(&a->link);	136	link_initialize(&a->link);
137	a->type = type;	137	a->type = type;
138	a->size = size;	138	a->size = size;
139	a->base = base;	139	a->base = base;
140		140
141	list_append(&a->link, &as->as_area_head);	141	list_append(&a->link, &as->as_area_head);
142		142
143	spinlock_unlock(&as->lock);	143	spinlock_unlock(&as->lock);
144	interrupts_restore(ipl);	144	interrupts_restore(ipl);
145		145
146	return a;	146	return a;
147	}	147	}
148		148
149	/** Initialize mapping for one page of address space.	149	/** Initialize mapping for one page of address space.
150	*	150	*
151	* This functions maps 'page' to 'frame' according	151	* This functions maps 'page' to 'frame' according
152	* to attributes of the address space area to	152	* to attributes of the address space area to
153	* wich 'page' belongs.	153	* wich 'page' belongs.
154	*	154	*
155	* @param a Target address space.	155	* @param as Target address space.
156	* @param page Virtual page within the area.	156	* @param page Virtual page within the area.
157	* @param frame Physical frame to which page will be mapped.	157	* @param frame Physical frame to which page will be mapped.
158	*/	158	*/
159	void as_set_mapping(as_t *as, __address page, __address frame)	159	void as_set_mapping(as_t *as, __address page, __address frame)
160	{	160	{
161	as_area_t a, area = NULL;	161	as_area_t a, area = NULL;
162	link_t *cur;	162	link_t *cur;
163	ipl_t ipl;	163	ipl_t ipl;
164		164
165	ipl = interrupts_disable();	165	ipl = interrupts_disable();
166	spinlock_lock(&as->lock);	166	spinlock_lock(&as->lock);
167		167
168	/*	168	/*
169	* First, try locate an area.	169	* First, try locate an area.
170	*/	170	*/
171	for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {	171	for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
172	a = list_get_instance(cur, as_area_t, link);	172	a = list_get_instance(cur, as_area_t, link);
173	spinlock_lock(&a->lock);	173	spinlock_lock(&a->lock);
174		174
175	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {	175	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
176	area = a;	176	area = a;
177	break;	177	break;
178	}	178	}
179		179
180	spinlock_unlock(&a->lock);	180	spinlock_unlock(&a->lock);
181	}	181	}
182		182
183	if (!area) {	183	if (!area) {
184	panic("page not part of any as_area\n");	184	panic("page not part of any as_area\n");
185	}	185	}
186		186
187	/*	187	/*
188	* Note: area->lock is held.	188	* Note: area->lock is held.
189	*/	189	*/
190		190
191	page_mapping_insert(as, page, frame, get_area_flags(area));	191	page_mapping_insert(as, page, frame, get_area_flags(area));
192		192
193	spinlock_unlock(&area->lock);	193	spinlock_unlock(&area->lock);
194	spinlock_unlock(&as->lock);	194	spinlock_unlock(&as->lock);
195	interrupts_restore(ipl);	195	interrupts_restore(ipl);
196	}	196	}
197		197
198	/** Handle page fault within the current address space.	198	/** Handle page fault within the current address space.
199	*	199	*
200	* This is the high-level page fault handler.	200	* This is the high-level page fault handler.
201	* Interrupts are assumed disabled.	201	* Interrupts are assumed disabled.
202	*	202	*
203	* @param page Faulting page.	203	* @param page Faulting page.
204	*	204	*
205	* @return 0 on page fault, 1 on success.	205	* @return 0 on page fault, 1 on success.
206	*/	206	*/
207	int as_page_fault(__address page)	207	int as_page_fault(__address page)
208	{	208	{
209	link_t *cur;	209	link_t *cur;
210	as_area_t a, area = NULL;	210	as_area_t a, area = NULL;
211	__address frame;	211	__address frame;
212		212
213	ASSERT(AS);	213	ASSERT(AS);
214	spinlock_lock(&AS->lock);	214	spinlock_lock(&AS->lock);
215		215
216	/*	216	/*
217	* Search this areas of this address space for presence of 'page'.	217	* Search this areas of this address space for presence of 'page'.
218	*/	218	*/
219	for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {	219	for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {
220	a = list_get_instance(cur, as_area_t, link);	220	a = list_get_instance(cur, as_area_t, link);
221	spinlock_lock(&a->lock);	221	spinlock_lock(&a->lock);
222		222
223	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {	223	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
224		224
225	/*	225	/*
226	* We found the area containing 'page'.	226	* We found the area containing 'page'.
227	* TODO: access checking	227	* TODO: access checking
228	*/	228	*/
229	area = a;	229	area = a;
230	break;	230	break;
231	}	231	}
232		232
233	spinlock_unlock(&a->lock);	233	spinlock_unlock(&a->lock);
234	}	234	}
235		235
236	if (!area) {	236	if (!area) {
237	/*	237	/*
238	* No area contained mapping for 'page'.	238	* No area contained mapping for 'page'.
239	* Signal page fault to low-level handler.	239	* Signal page fault to low-level handler.
240	*/	240	*/
241	spinlock_unlock(&AS->lock);	241	spinlock_unlock(&AS->lock);
242	return 0;	242	return 0;
243	}	243	}
244		244
245	/*	245	/*
246	* Note: area->lock is held.	246	* Note: area->lock is held.
247	*/	247	*/
248		248
249	/*	249	/*
250	* In general, there can be several reasons that	250	* In general, there can be several reasons that
251	* can have caused this fault.	251	* can have caused this fault.
252	*	252	*
253	* - non-existent mapping: the area is a scratch	253	* - non-existent mapping: the area is a scratch
254	* area (e.g. stack) and so far has not been	254	* area (e.g. stack) and so far has not been
255	* allocated a frame for the faulting page	255	* allocated a frame for the faulting page
256	*	256	*
257	* - non-present mapping: another possibility,	257	* - non-present mapping: another possibility,
258	* currently not implemented, would be frame	258	* currently not implemented, would be frame
259	* reuse; when this becomes a possibility,	259	* reuse; when this becomes a possibility,
260	* do not forget to distinguish between	260	* do not forget to distinguish between
261	* the different causes	261	* the different causes
262	*/	262	*/
263	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));	263	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
264	memsetb(PA2KA(frame), FRAME_SIZE, 0);	264	memsetb(PA2KA(frame), FRAME_SIZE, 0);
265		265
266	/*	266	/*
267	* Map 'page' to 'frame'.	267	* Map 'page' to 'frame'.
268	* Note that TLB shootdown is not attempted as only new information is being	268	* Note that TLB shootdown is not attempted as only new information is being
269	* inserted into page tables.	269	* inserted into page tables.
270	*/	270	*/
271	page_mapping_insert(AS, page, frame, get_area_flags(area));	271	page_mapping_insert(AS, page, frame, get_area_flags(area));
272		272
273	spinlock_unlock(&area->lock);	273	spinlock_unlock(&area->lock);
274	spinlock_unlock(&AS->lock);	274	spinlock_unlock(&AS->lock);
275		275
276	return 1;	276	return 1;
277	}	277	}
278		278
279	/** Switch address spaces.	279	/** Switch address spaces.
280	*	280	*
281	* @param old Old address space or NULL.	281	* @param old Old address space or NULL.
282	* @param new New address space.	282	* @param new New address space.
283	*/	283	*/
284	void as_switch(as_t old, as_t new)	284	void as_switch(as_t old, as_t new)
285	{	285	{
286	ipl_t ipl;	286	ipl_t ipl;
287	bool needs_asid = false;	287	bool needs_asid = false;
288		288
289	ipl = interrupts_disable();	289	ipl = interrupts_disable();
290	spinlock_lock(&as_lock);	290	spinlock_lock(&as_lock);
291		291
292	/*	292	/*
293	* First, take care of the old address space.	293	* First, take care of the old address space.
294	*/	294	*/
295	if (old) {	295	if (old) {
296	spinlock_lock(&old->lock);	296	spinlock_lock(&old->lock);
297	ASSERT(old->refcount);	297	ASSERT(old->refcount);
298	if((--old->refcount == 0) && (old != AS_KERNEL)) {	298	if((--old->refcount == 0) && (old != AS_KERNEL)) {
299	/*	299	/*
300	* The old address space is no longer active on	300	* The old address space is no longer active on
301	* any processor. It can be appended to the	301	* any processor. It can be appended to the
302	* list of inactive address spaces with assigned	302	* list of inactive address spaces with assigned
303	* ASID.	303	* ASID.
304	*/	304	*/
305	ASSERT(old->asid != ASID_INVALID);	305	ASSERT(old->asid != ASID_INVALID);
306	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);	306	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
307	}	307	}
308	spinlock_unlock(&old->lock);	308	spinlock_unlock(&old->lock);
309	}	309	}
310		310
311	/*	311	/*
312	* Second, prepare the new address space.	312	* Second, prepare the new address space.
313	*/	313	*/
314	spinlock_lock(&new->lock);	314	spinlock_lock(&new->lock);
315	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {	315	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
316	if (new->asid != ASID_INVALID)	316	if (new->asid != ASID_INVALID)
317	list_remove(&new->inactive_as_with_asid_link);	317	list_remove(&new->inactive_as_with_asid_link);
318	else	318	else
319	needs_asid = true; /* defer call to asid_get() until new->lock is released */	319	needs_asid = true; /* defer call to asid_get() until new->lock is released */
320	}	320	}
321	SET_PTL0_ADDRESS(new->page_table);	321	SET_PTL0_ADDRESS(new->page_table);
322	spinlock_unlock(&new->lock);	322	spinlock_unlock(&new->lock);
323		323
324	if (needs_asid) {	324	if (needs_asid) {
325	/*	325	/*
326	* Allocation of new ASID was deferred	326	* Allocation of new ASID was deferred
327	* until now in order to avoid deadlock.	327	* until now in order to avoid deadlock.
328	*/	328	*/
329	asid_t asid;	329	asid_t asid;
330		330
331	asid = asid_get();	331	asid = asid_get();
332	spinlock_lock(&new->lock);	332	spinlock_lock(&new->lock);
333	new->asid = asid;	333	new->asid = asid;
334	spinlock_unlock(&new->lock);	334	spinlock_unlock(&new->lock);
335	}	335	}
336	spinlock_unlock(&as_lock);	336	spinlock_unlock(&as_lock);
337	interrupts_restore(ipl);	337	interrupts_restore(ipl);
338		338
339	/*	339	/*
340	* Perform architecture-specific steps.	340	* Perform architecture-specific steps.
341	* (e.g. write ASID to hardware register etc.)	341	* (e.g. write ASID to hardware register etc.)
342	*/	342	*/
343	as_install_arch(new);	343	as_install_arch(new);
344		344
345	AS = new;	345	AS = new;
346	}	346	}
347		347
348	/** Compute flags for virtual address translation subsytem.	348	/** Compute flags for virtual address translation subsytem.
349	*	349	*
350	* The address space area must be locked.	350	* The address space area must be locked.
351	* Interrupts must be disabled.	351	* Interrupts must be disabled.
352	*	352	*
353	* @param a Address space area.	353	* @param a Address space area.
354	*	354	*
355	* @return Flags to be used in page_mapping_insert().	355	* @return Flags to be used in page_mapping_insert().
356	*/	356	*/
357	int get_area_flags(as_area_t *a)	357	int get_area_flags(as_area_t *a)
358	{	358	{
359	int flags;	359	int flags;
360		360
361	switch (a->type) {	361	switch (a->type) {
362	case AS_AREA_TEXT:	362	case AS_AREA_TEXT:
363	flags = PAGE_EXEC \| PAGE_READ \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;	363	flags = PAGE_EXEC \| PAGE_READ \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;
364	break;	364	break;
365	case AS_AREA_DATA:	365	case AS_AREA_DATA:
366	case AS_AREA_STACK:	366	case AS_AREA_STACK:
367	flags = PAGE_READ \| PAGE_WRITE \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;	367	flags = PAGE_READ \| PAGE_WRITE \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;
368	break;	368	break;
369	default:	369	default:
370	panic("unexpected as_area_type_t %d", a->type);	370	panic("unexpected as_area_type_t %d", a->type);
371	}	371	}
372		372
373	return flags;	373	return flags;
374	}	374	}
375		375
376	/** Create page table.	376	/** Create page table.
377	*	377	*
378	* Depending on architecture, create either address space	378	* Depending on architecture, create either address space
379	* private or global page table.	379	* private or global page table.
380	*	380	*
381	* @param flags Flags saying whether the page table is for kernel address space.	381	* @param flags Flags saying whether the page table is for kernel address space.
382	*	382	*
383	* @return First entry of the page table.	383	* @return First entry of the page table.
384	*/	384	*/
385	pte_t *page_table_create(int flags)	385	pte_t *page_table_create(int flags)
386	{	386	{
387	ASSERT(as_operations);	387	ASSERT(as_operations);
388	ASSERT(as_operations->page_table_create);	388	ASSERT(as_operations->page_table_create);
389		389
390	return as_operations->page_table_create(flags);	390	return as_operations->page_table_create(flags);
391	}	391	}
392		392

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(root)/kernel/trunk/generic/src/mm/as.c – Rev 823 → 840